1, Field of the invention
The present invention relates to an ultrasonic probe and ultrasonic diagnostic equipment provided with an ultrasonic transducer used for ultrasonic observation.
2, Related Art Statement
In an ultrasonic probe and an ultrasonic endoscope which produce an ultrasonic image by mechanically rotating or shaking an ultrasonic transducer, an acoustic medium which transmits an ultrasonic wave is allowed to fill in between the ultrasonic transducer and a sheath storing it or a cap.
Conventionally, liquid paraffin having low toxicity to a living body, water, carboxymethyl cellulose (CMC) aqueous solutions, and the like have been used as the acoustic medium.
However, conventional acoustic media in ultrasonic probes and ultrasonic scopes-which produced ultrasonic images by mechanically rotating or shaking ultrasonic transducers had problems as described below.
When water or an aqueous solution of carboxymethyl cellulose or the like is used as the acoustic medium, the acoustic medium is decreased with time due to volatilization of water and, therefore, the acoustic medium has to be periodically replenished.
When commonly used conventional liquid paraffin having a kinematic viscosity on the order of 70 mm2/s is used as the acoustic medium, decrease of the capacity of the acoustic medium with time due to volatilization is reduced. However, regarding ultrasonic transducers of high frequencies of 10 MHz or more, since ultrasonic attenuation in the liquid paraffin is large, it is difficult to render adequate characteristics.